Systematic investigation of partonic collectivity through centrality dependence of elliptic flow of multi-strange hadrons in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV in STAR

Abstract

We present the measurement of centrality dependence of multi-strange hadron ($Ω$, $Ξ$ and $ϕ$) elliptic flow ($v_{2}$) at mid-rapidity in Au+Au collision at $\sqrt{s_{NN}}$ = 200 GeV. We investigate number-of-constituents quark (NCQ) scaling of identified hadrons $v_{2}$ for different collision centralities. Maximum deviation from ideal NCQ scaling observed at the level of 10% for centrality 30-80$%$ at $(m_{T} - m_{0})/n_{q}$ $>$ 0.6 GeV/$c^{2}$. This may indicate smaller contribution to the collectivity from the partonic phase in the peripheral collisions. We also observe the mass ordering of $v_{2}$ break down between proton and $ϕ$-meson for $p_{T}$ $< $1 GeV/$c$. This could be due to the effect of later stage hadronic interactions on $v_{2}$.

4 pages, 3 figures, Quark Matter 2012 proceedings